TW201515735A - Forging device - Google Patents

Abstract

This invention provides a forging device and forging method that enable to easily achieve both the formation of a highly accurate groove on the inner periphery of a processed object, and the improvement in productivity. The forging device comprises a die (20), an inner punch (30), and an inner punch driving section (50) that makes the inner punch (30) to repeatedly move between a striking position where the inner punch (30) strikes the processed object (10) and a separating position where the inner punch (30) is away from the processed object (10). The inner punch (30) comprises a forging section (32) and a groove forming section (34). The forging section (32) is formed at a position facing the processed object (10), and has a shape capable of forging the inner periphery (10a) of the processed object (10) so as to form the inner periphery (10a) into a standard inner periphery (10b). The groove forming section (34) projects outwards in the feeding direction from the rear end of the forging section (32), and has a shape capable of forming a groove (10c) on the standard inner periphery (10b).

Description

Forging device

The present invention relates to a forging device.

Conventionally, a workpiece having a forged inner circumferential surface is processed by a key groove or a bolt groove (hereinafter simply referred to as "groove") in the inner diameter thereof. For example, Patent Document 1 discloses a molding method in which an annular intermediate molded article having a through hole at the center is formed by forging a disk-shaped workpiece, and then the intermediate molded article is broached. The inner peripheral surface is formed with a groove to form a final molded article. [Prior Art Literature] [Patent Literature]

Patent Document 1: Japanese Laid-Open Patent Publication No. 2013-040652

[The problem that the invention wants to solve]

In the forming method described in the above-mentioned Patent Document 1, since the forging and the broaching are separately performed on different apparatuses, there are problems in that the workpiece is obtained from the workpiece to obtain the desired final molded article. It takes a long time to work and it is difficult to increase productivity. Specifically, in order to carry out the molding method described in Patent Document 1, first, the workpiece is first clamped to a nip portion of a forging device for forging a workpiece, and the clamped portion is processed. The piece is forged to form the intermediate molded article. Thereafter, the intermediate molded article is taken out from the nip portion of the forging device, and the intermediate molded article is sandwiched between the nip portions of the broaching machine. Thereafter, the inner peripheral surface of the intermediate molded article is cut by a broach to form a groove. Thus, the above-described forming method is accompanied by a very complicated work.

Further, since the forming step of the intermediate molded article and the step of forming the groove for the intermediate molded article are performed on different devices, the processing accuracy of the groove may be lowered. Specifically, the tolerance of the intermediate molded article formed by forging the workpiece by the forging device may cause the intermediate molded article to be clamped to the nip portion of the broaching device in a posture slightly deviating from the standard posture. . In this case, the machining accuracy of the broaching process is significantly reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a forging device and a forming method which can easily achieve the dual purpose of improving productivity and forming a groove of high precision on an inner diameter. [The way to solve the problem]

In order to solve the above problems, the inventors of the present invention have conceived a method of forming an inner peripheral surface on a workpiece and forming a groove on the inner peripheral surface by the same inner punch. However, when the inner peripheral surface is formed on the workpiece and the groove is formed at the same time, the friction generated between the inner punch and the workpiece becomes large, and the inner punch may be worn.

Accordingly, the present invention provides a forging device comprising: a forging die for placing a workpiece having a through hole; and an inner punch for processing an inner peripheral surface of the through hole surrounding the workpiece; The inner punch driving portion is configured to repeatedly shift the inner punch between the impact position and the exit position, wherein the impact position is that the inner punch is displaced toward the feeding direction of the workpiece to impact the a position of the workpiece, the leaving position being a position in which the inner punch is displaced away from the feeding direction and away from the workpiece; wherein the inner punch has a forged portion for forging the processed portion An inner peripheral surface of the member; and a groove forming portion formed at a rear of the forged portion in the feeding direction; the forged portion being formed in the feeding direction opposite to the workpiece placed on the forging die a position having a shape in which an inner circumferential surface of a cross section perpendicular to the feeding direction is a reference inner circumferential surface that is uniform throughout the feeding direction by forging the inner circumferential surface of the workpiece; and The groove forming portion has as Shape: in the feeding direction of the forged portion protruding from the rear end to the outside may be formed on the inner peripheral surface of the groove reference.

According to the present invention, after the reference inner circumferential surface is formed on the workpiece by the forged portion, a groove is formed on the reference inner circumferential surface by the groove forming portion, and the inner punch is repeatedly displaced by the displacement and Leaving the workpiece, which will greatly reduce the friction generated between the inner punch and the workpiece, the wear of the forged portion and the groove forming portion is suppressed, so that a single inner punch can be used. The inner peripheral surface of the workpiece is forged by a single step and a groove is formed on the inner circumferential surface of the reference. Specifically, the forged portion forms a uniform reference inner peripheral surface on the workpiece on the inner peripheral surface of the cross section perpendicular to the feed direction in the feed direction, and is formed by the groove. Since the groove is formed on the inner circumferential surface of the reference, the groove reduction rate is fixed at the reference inner circumferential surface, and the pressure reduction acting on the groove forming portion is uniform, that is, the pressure acting on the groove forming portion is uniform. The friction generated between the inner punch and the workpiece will be reduced. Further, the above-described operation is performed to greatly reduce the friction generated between the inner punch and the workpiece: the inner punch is repeatedly impacted and displaced from the workpiece, that is, the inner punch is facing the inner punch. The feed direction is pressed into the remaining material of the workpiece to be produced by the workpiece, so that the internal punch is excessively large, the inner punch is separated from the workpiece, whereby the resistance is reduced. The workpiece is pressed in the feed direction. Therefore, the wear of the forged portion and the groove forming portion is suppressed, so that the inner peripheral surface of the forged workpiece and the processing for forming the groove on the reference inner peripheral surface can be performed in a single step. Further, the conventional broaching step is omitted, and the man-hours from the workpiece to the desired molded article are reduced. Therefore, the conventionally performed step of arranging the forged intermediate molded article on the broaching apparatus independently of the forging device is omitted, thereby avoiding the groove caused by the tolerance of the intermediate molded article. The machining accuracy is lowered, and a high-precision groove can be formed.

In this case, it is preferable that the forged portion includes a guide portion that extends from the distal end of the groove forming portion in the feeding direction in the feeding direction and has an outer peripheral surface parallel to the feeding direction. .

In this way, in a state where the guide portion is guided by the reference inner circumferential surface, that is, in a state where the guide portion is displaced in a direction perpendicular to the feeding direction, by the feeding direction and the leaving direction The groove forming portion that is displaced forms a groove on the reference inner circumferential surface, so that the processing accuracy of the groove is further improved.

Further, in the invention, it is preferable to further include an outer punch disposed outside the inner punch; the forging die has an outer shape forming portion that surrounds the outer peripheral surface of the workpiece and can be formed to be processed The shape of the outer shape of the piece; the outer punch has a shape in which the workpiece is pressed toward the feeding direction to expand the workpiece and make the outer surface of the workpiece The outer shape forming portion.

In this way, the inner diameter and the outer diameter of the workpiece can be processed without removing the workpiece from the forging die. Further, since the outer punch has a shape that can face the outer shape forming portion The workpiece is pressed in the feeding direction to expand the workpiece, and the outer surface of the workpiece is brought into close contact with the outer shape forming portion. Therefore, the outer punch is pressed toward the outer shape forming portion. In the state of the workpiece, that is, the workpiece is processed by the inner punch in a state where the displacement of the workpiece relative to the forging die in a direction perpendicular to the feeding direction is limited by the forging die. Therefore, the machining accuracy of the inner diameter of the workpiece is further improved.

Further, in the invention, it is preferable that the inner punch driving portion has a press-fitting force setting portion that presses the inner punch into the workpiece, and the inner punch is initially from the workpiece The position of the contact increases as the amount of displacement of the displacement of the inner punch in the feed direction increases.

Thus, the inner peripheral surface of the workpiece can be processed smoothly by the inner punch. In general, as the amount of displacement of the inner punch to the displacement in the feed direction is increased, the remaining material of the workpiece is generated, and thus the press-in force is gradually increased. Therefore, for example, when the press-in force is fixed, the displacement amount of the inner punch displaced in the feed direction (the processing speed at which the inner peripheral surface is machined by the inner punch) is gradually lowered. On the other hand, in the present invention, as the amount of displacement in which the inner punch is displaced in the feeding direction is increased, the pressing force is gradually increased, so that the inner peripheral surface can be smoothly processed, whereby the productivity is improved.

Further, in the invention, it is preferable that the inner punch driving portion has a speed adjusting portion that adjusts a speed at which the inner punch is displaced from the impact position to the separated position.

Thus, the material and shape of the workpiece can be flexibly handled, and the workpiece can be processed. [Effects of the Invention]

As described above, according to the present invention, it is possible to provide a forging device and a forming method which can easily achieve the dual purpose of forming a high-precision groove on the inner diameter and improving productivity.

[Preferred form of implementing the invention]

Hereinafter, a forging device according to an embodiment of the present invention will be described with reference to Figs. 1 to 5 .

As shown in FIGS. 1 and 2, the forging device of the present embodiment includes a forging die 20, an inner punch 30, and an outer punch 40 on which the workpiece 10 can be placed. Further, as shown in FIG. 4, the present forging device includes an inner punch driving portion 50 for driving the inner punch 30. The forging forming device can form a bevel gear, a differential side gear, a hyperbolic ring gear, a spur gear, a sleeve yoke, and a molded article having other irregular shapes. Further, in Fig. 1, the left side of the central axis O of the inner punch 30 shows the state in which the inner punch 30 and the outer punch 40 are both in contact with the workpiece 10, and the right side of the central axis O is shown. The state in which the outer punch 40 presses the workpiece 10 to the forging die 20 and the inner punch 30 is processing the inner diameter of the workpiece 10 is processed. In Fig. 2, on the left side of the center axis O, the state in which the outer punch 40 pushes the workpiece 10 to the forging die 20 and the inner punch 30 is processing the inner diameter of the workpiece 10 is shown. The right side of the center axis O shows a state after the end of the machining of the inner diameter of the workpiece 10 by the inner punch 30. In the following description, the lower side of FIGS. 1 and 2 is referred to as the lower side or the front side, and the upper side of FIGS. 1 and 2 is referred to as the upper side or the rear side.

The workpiece 10 is an annular member having an inner peripheral surface 10a surrounding the through hole. Specifically, the workpiece 10 having the through hole is further formed by central perforation of the material formed by cold forging, warm forging or hot forging. Further, on the right side of the central axis O of FIG. 1 and the left side of the central axis O of FIG. 2, the position of the inner peripheral surface 10a before processing is shown by a two-dot chain line.

The die 20 has an outer shape forming portion 22 and has a shape in which the workpiece 10 can be placed and the outer shape of the workpiece 10 can be formed. The outer shape forming portion 22 has a concave shape surrounding the periphery of the workpiece 10. The forging die 20 of the present embodiment has an inner peripheral surface 24 that surrounds a space for allowing the inner punch 30 and the blank scrap 14 (see FIG. 2) of the workpiece 10 to be inserted. The lower end of the outer shape forming portion 22 is connected to the upper end of the inner peripheral surface 24.

As shown in FIG. 1 and FIG. 2, the inner punch 30 is a tool that processes the inner circumferential surface 10a of the workpiece while repeatedly shifting in the vertical direction. More specifically, the inner punch 30 processes the inner peripheral surface 10a of the workpiece while repeatedly shifting between the impact position and the exit position, wherein the impact position is the inner punch 30 facing the workpiece 40. The feed direction (lower in FIGS. 1 and 2) is displaced to impact the position of the workpiece 10, which is the direction in which the inner punch 30 is opposite to the feed direction (above in FIGS. 1 and 2). The displacement then leaves the position of the workpiece 10. This action of the inner punch 30 is achieved by the inner punch drive unit 50. This will be explained in detail later. Specifically, the inner punch 30 has a forged portion 32 for forging the inner peripheral surface 10a of the workpiece 10, and a groove forming portion 34 for forming a groove such as a key groove or a bolt groove on the workpiece 10.

The forged portion 32 is formed at a position facing the workpiece 10 placed on the forging die 20. As shown in FIG. 2, the forged portion 32 is formed by forging the inner peripheral surface 10a of the workpiece 10, and further forming a reference inner peripheral surface 10b on the workpiece 10. The reference inner circumferential surface 10b is an inner circumferential surface having a uniform outer shape in the axial direction of the inner circumferential surface of the cross section perpendicular to the axial direction of the central axis O. As shown in FIG. 3, the forged portion 32 has a flat portion 32a parallel to a surface perpendicular to the axial direction, an inclined portion 32b formed in a shape extending upward from the flat portion 32a in the axial direction, and a guide portion 32c. It has an outer peripheral surface parallel to the axial direction (feeding direction). The flat portion 32a is formed at the top end of the inner punch 30 (lower end in Fig. 1). The inclined portion 32b has a shape in which the outer diameter thereof gradually increases from the outer edge of the flat portion 32a toward the upper side. The guide portion 32c has a shape that extends upward from the upper end of the inclined portion 32b and is connected to the groove forming portion 34, in other words, has a tip end (lower end in FIG. 1) extending from the groove forming portion 34 in the feeding direction and the inclined portion 32b. The shape of the outer edge is connected. The outer diameter of the guide portion 32c is larger than the outer diameter of the flat portion 32a. In the present embodiment, the flat portion 32a and the inclined portion 32b have a truncated cone shape, and the guide portion 32c has a columnar shape. That is, the inner circumferential surface 10a of the workpiece 10 is processed into the reference inner circumferential surface 10b by the guide portion 32c.

The groove forming portion 34 is formed in the feeding direction immediately after the forged portion 32 (the immediately upper side of the forged portion 32 in Fig. 1) for forming on the reference inner peripheral surface 10b formed by the guiding portion 32. groove. This groove forming portion 34 has a base portion 34a and a protruding portion 34b.

The base portion 34a has a shape that extends upward from the rear end of the guide portion 32c. In the present embodiment, the base portion 34a is formed in a shape that is long in the axial direction and has a cylindrical shape as a whole.

The protruding portion 34b has a shape that protrudes from the outer surface of the base portion 34a toward the outer side (the side away from the central axis O) and is long in the axial direction. The protruding portion 34b has a push-out portion, and the amount of protrusion toward the outside gradually increases from the rear end of the guide portion 32c. As shown in Fig. 3, in the present embodiment, the plurality of protruding portions 34b are arranged around the central axis O with the same pitch. In addition, in FIG. 1 and FIG. 2, only the protrusion part 34b in the left-right side of this figure is shown.

When the inner punch 30 is driven by the inner punch driving unit 50, the forged portion 32 that is displaced by the reciprocating motion in the upper and lower directions forms the reference inner circumference on the inner circumferential surface 10a of the workpiece 10 first. After the surface 10b, the groove forming portion 34 that is displaced by the reciprocating motion in the downward direction is continued, and the groove 10c is formed on the reference inner circumferential surface 10b. Thereafter, when the machining of the inner diameter of the workpiece 10 by the inner punch 30 is completed, the blank scrap 14 of the workpiece 10 falls downward on the inner side of the inner circumferential surface 24 of the forging die 20.

The outer punch 40 is disposed outside the inner punch 30. The outer punch 40 has a cylindrical shape for pressing the workpiece 10 placed on the outer shape forming portion 22 of the die 20 in the feeding direction. Specifically, a pressing portion 42 parallel to the surface perpendicular to the axial direction is formed at the lower end of the outer punch 40, and the pressing portion 42 presses the peripheral edge portion of the workpiece 10 in the feeding direction. Thereby, the workpiece 10 is expanded, and the outer surface of the workpiece 10 is in close contact with the outer shape forming portion 22. The outer punch 40 is displaceable in the up and down direction independently of the inner punch 30. Specifically, the outer punch 40 is driven by an outer punch driving portion (not shown) for driving the outer punch 40. In the present embodiment, the outer punch 40 is driven in the feeding direction before the inner punch 30, and the workpiece 10 is pressed against the outer shape forming portion 22.

Further, a lubricating oil supply flow path 44 is formed in the outer punch 40. The lubricating oil supply flow path 44 penetrates the outer punch 40 in a direction perpendicular to the axial direction. In the present embodiment, the lubricating oil supply flow path 44 is formed at four positions around the central axis O at intervals of 90 degrees. The lubricating oil supplied from the outside of the outer punch 40 by the lubricating oil supply passage 44 is sprayed toward the outer surface of the inner punch 30. This lubricating oil flows down along the outer surface of the inner punch 30, and further reaches the inner peripheral surface 10a of the workpiece 10. Thereby, the friction between the inner punch 30 and the workpiece 10 is reduced. In the present embodiment, the lubricating oil is injected at a pace of once per second.

Next, the inner punch driving unit 50 will be described with reference to Fig. 4 .

The inner punch drive unit 50 has a hydraulic cylinder 500 that can expand and contract in the vertical direction, and a hydraulic system 502 that drives the hydraulic cylinder 500 in the telescopic direction.

The hydraulic cylinder 500 has a piston 507, a cylinder body 501 that accommodates the piston 507 so as to be movable up and down, and a push rod 508. The piston 507 is filled in the cylinder body 501 such that the cylinder body 501 is partitioned into an upper head chamber 501a and a lower pusher chamber 501b. The push rod 508 extends downward from the piston 507 and beyond the lower end of the cylinder body 501. The lower end 508a of the push rod 508 is coupled to the upper end of the inner punch 30. Thereby, the inner punch 30 is displaced in the vertical direction by the expansion and contraction of the hydraulic cylinder 500, that is, the displacement of the piston 507 and the push rod 508 in the vertical direction.

The hydraulic system 502 includes a hydraulic pump 503, a discharge flow rate adjustment unit 505, a switching valve 510, a sequence valve 530, a pressure setting unit 536, a flow rate adjustment valve 540, a flow rate adjustment unit 546, a buffer unit 550, and an initial position adjustment unit 560.

The hydraulic pump 503 is a variable displacement pump, and the discharge flow rate can be adjusted based on an electric signal output from the discharge flow rate adjustment unit 505. The hydraulic pump 503 is coupled to a motor 504 of adjustable speed. That is, the discharge flow rate from the hydraulic pump 503 can be adjusted by both the regulator and the rotational speed of the motor 504. The rotation speed of the regulator and the motor 504, that is, the discharge amount of the hydraulic oil from the hydraulic pump 503 is adjusted by the discharge amount adjusting portion 505 connected to the hydraulic pump 503 and the motor 504.

The switching valve 510 is connected to the hydraulic pump 503 via the first oil passage 521, is connected to the cylinder head chamber 501a via the second oil passage 522, is connected to the push rod chamber 501b via the third oil passage 523, and is connected to the oil groove via the fourth oil passage 524. T connection. The switching valve 510 is a hydraulically controlled two-position switching valve that can switch the spool between the cylinder down position 510b and the cylinder up position 510a, wherein the cylinder down position 510b is via the first oil passage 521 and the second oil The path 522 introduces the hydraulic oil discharged from the hydraulic pump 503 into the cylinder head chamber 501a, and introduces the return oil from the push rod chamber 501b to the position of the spool when the oil tank T is introduced via the third oil passage 523 and the fourth oil passage 524. The cylinder up position 510a is introduced into the cylinder head chamber 501a via the first oil passage 521 and the third oil passage 523, and is introduced via the second oil passage 522 and the fourth oil passage 524. The position of the spool when the return oil is introduced from the head chamber 501a to the oil groove T.

The switching valve 510 has a first control chamber 511, a second control chamber 512, and a spring 513. The spring 513 constantly urges the spool toward the direction in which the spool is in the cylinder down position 510b. Therefore, when the control pressure does not act on the first control chamber 511, the spool is maintained at the cylinder down position 510b. The first control chamber 511 is connected to the first oil passage 521 via a first control line 531. When the control pressure is supplied from the first oil passage 521 to the first control chamber 511 by the first control line 531, the control pressure is The strut is switched to the cylinder up position 510a against the urging force of the spring 513. The second control chamber 512 is connected to the fourth oil passage 524 via a second control line 532. The control pressure supplied from the fourth oil passage 524 to the second control chamber 512 by the second control line 532 is together with the spring 513. The strut is biased in a direction that causes the spool to move in the down position 510b.

The sequence valve 530 is disposed on the way of the first control line 531, and the opening and closing of the first control line 531 is performed by opening and closing the valve. When the primary pressure, that is, the pressure of the first oil passage 521 connected to the cylinder head chamber 501a via the second oil passage 522 exceeds the set pressure set by the pressure setting portion 536, the sequence valve 530 is opened. More specifically, the inner punch 30 contacts the workpiece 10 and receives resistance from the workpiece 10, thereby suppressing the lowering of the inner punch 30 and the piston 507 of the hydraulic cylinder 500, and acting on the cylinder head chamber. The pressure of 501a and the pressure of the first oil passage 521 rise, and when the pressure of the first oil passage 521 exceeds the pressure corresponding to the set pressure, the sequence valve 530 is opened. Then, the first control line 531 is opened, and the control pressure acts on the first control chamber 511. In addition, at the same time, the hydraulic oil supplied to the first control line 531 is also supplied to the second control line 532 through the throttle valve 535. Further, when the pressure of the head chamber 501a is lower than the set pressure, the sequence valve 530 is closed.

The sequence valve 530 of the present embodiment is a proportional solenoid type valve, and the set pressure of the sequence valve 530 can be adjusted by the external pressure setting unit 536. Since the set pressure of the sequence valve 530 corresponds to the press-in force of the inner punch 30 to press the workpiece 10, the pressure setting unit 536 corresponds to the "pressing force setting unit". As shown in FIG. 5, the pressure setting portion 536 increases the set pressure in such a manner that the inner punch 30 faces the inner punch 30 from the position (initial position) where it is initially in contact with the workpiece 10. It increases as the amount of displacement of the directional displacement increases.

The flow regulating valve 540 is disposed on the second control line 532. The flow rate of the working oil flowing into the second control chamber 512, that is, the control pressure acting on the second control chamber 512 is adjusted by adjusting the opening degree of the flow regulating valve 540. The flow rate adjusting valve 540 of the present embodiment is a proportional electromagnetic type valve, and the opening degree of the flow rate adjusting valve 540 can be adjusted by the external flow rate adjusting unit 546. If the opening degree of the flow rate adjusting valve 540 becomes small, the control pressure acting on the second control chamber 512 becomes small, and therefore, the speed at which the spool returns to the cylinder down position 510b becomes small, thereby further causing the piston 507 of the hydraulic cylinder 500 and The speed at which the inner punch 30 rises also becomes small. In other words, the flow rate adjusting unit 546 constitutes a "speed adjusting unit" for adjusting the speed at which the inner punch 30 is displaced in the separating direction by adjusting the opening degree of the flow rate adjusting valve 540. In the present embodiment, the displacement speed of the hydraulic cylinder 500 can be adjusted between 5 pm and 800 spm by the speed adjusting portion.

The buffer portion 550 is provided on the fourth oil passage 524 for reducing the vibration of the hydraulic oil in each oil passage. The buffer portion 550 has an accumulator 551 that can store hydraulic oil, a throttle valve 552 that is disposed on a side of the fourth oil passage 524 that is closer to the oil groove T than the accumulator 551, and a check valve 553, and the section Flow valves 552 are connected in parallel.

The initial position adjusting portion 560 is for adjusting the initial position of the piston 507 and the inner punch 30 in the hydraulic cylinder 500 in the vertical direction. The initial position adjusting unit 560 includes an electromagnetic switching valve 561, a back pressure holding portion 566 including a check valve, and an adjusting portion 567 including a control type variable flow rate adjusting valve. The electromagnetic switching valve 561 is an electromagnetic three-position switching valve that is switched between three positions of a neutral position 561a, a cylinder down position 561b, and a cylinder up position 561c. The electromagnetic switching valve 561 is connected to the control line 564, the second oil passage 522, and the third oil passage 523. The operator switches the position of the electromagnetic switching valve 561 from the outside, thereby adjusting the initial positions of the hydraulic cylinder 500 and the inner punch 30. Specifically, the operator sets the position at which the lower end of the inner punch 30 abuts against the upper end of the workpiece 10 as the initial position.

Further, control detection valves 571, 572 are provided on the second oil passage 522 and the third oil passage 523, respectively, and the pilot ports of these valves are connected to the control line or the oil sump line by the switching valve 573.

The control detecting valves 571, 572 are operated in such a manner that the pusher 508 and the inner punch 30 are both open and up, and the control detecting valves 571, 572 are both open, and only the inner punch 30 is adjusted by the initial position adjusting portion 560. The control detection valves 571, 572 are all closed at the lower end position. Thereby, the initial position adjustment can be performed without worrying about leakage inside the switching valve 510.

Further, a safety valve 576 is provided in the oil passage 575 branched from the first oil passage 521. The safety valve 576 can be used as an unloading valve. That is, the oil chamber on the spring side of the safety valve 576 is sequentially connected to the oil sump line via the pressure reducing valve 577, the throttle valve 578, and the electromagnetic valve 579, and when the electromagnetic valve 579 is operated to the open position, by the spring side The oil chamber communicates with the oil sump, and the safety valve 576 functions as an unloading valve. Further, when the solenoid valve 579 is operated to the closed position, the communication between the oil chamber on the spring side and the oil groove is cut off, and the safety valve 576 functions as a general safety valve.

Next, a mechanism for repeatedly displacing the inner punch 30 up and down by the hydraulic cylinder 500 will be described with reference to Fig. 4 .

As shown in FIG. 4, in the initial state, the spool of the switching valve 510 is held at the cylinder down position 510b by the urging force of the spring 513. When the hydraulic pump 503 is driven in this state, the hydraulic oil discharged from the hydraulic pump 503 is supplied to the cylinder head chamber 501a via the first oil passage 521 and the second oil passage 522, whereby the hydraulic cylinder 500 is extended. (The piston 507 and the push rod 508 are displaced to the lower side in Fig. 4), and therefore, the inner punch 30 is displaced downward, i.e., in the feed direction.

Thereafter, when the inner punch 30, more specifically the forged portion 32, impacts the workpiece 10, the inner punch 30 receives resistance from the residual material 12 of the workpiece 10, thereby causing the inner punch 30 and the piston 507. The drop is suppressed, whereby the pressure in the head chamber 501a and the pressure of the first oil passage 521 as the pump line rise. When the pressure exceeds the set pressure of the sequence valve 530, the sequence valve 530 opens to open the first control line 531, whereby the control pressure is increased to the first control chamber 511 by the first control line 531. Thus, the spool of the switching valve 510 is switched to the cylinder up position 510a. Thereby, the hydraulic oil discharged from the hydraulic pump 503 is supplied to the pusher chamber 501b via the first oil passage 521 and the third oil passage 523, and the hydraulic cylinder 500 is contracted (the piston 507 is displaced upward in FIG. 4). Therefore, the inner punch 30 is displaced upward, that is, in the direction of departure. Then, since the pressure in the head chamber 501a and the pressure of the first oil passage 521 are lower than the set pressure of the sequence valve 530, the sequence valve 530 is closed, thereby cutting off the first control line 531. Therefore, the spool of the switching valve 510 is biased by the spring 513 and subjected to a control pressure applied to the second control chamber 512, thereby switching the spool to the cylinder down position 510b.

As described above, by automatically switching the spool between the cylinder down position 510b and the cylinder up position 510a, the piston 507 of the hydraulic cylinder 500 and the push rod 508 and the inner punch 30 are integrally formed toward each other. Repeat the displacement in the up and down direction. As described above, in this process, the set pressure of the sequence valve 530 is adjusted by the pressure setting portion 536 so that the set pressure of the sequence valve 530 gradually increases from a specific initial value with time.

Next, the processing steps of the workpiece 10 will be described.

First, the workpiece 10 is placed on the outer shape forming portion 22 of the die 20 . Thereafter, the outer punch 40 is driven downward by an outer punch driving unit (not shown), and the peripheral edge portion of the workpiece 10 is pressed downward by the pressing portion 42. At this time, the workpiece 10 is plastically deformed, the outer surface thereof is outwardly expanded, and the outer surface of the workpiece 10 is in close contact with the outer shape forming portion 22. Thereby, the outer shape of the workpiece 10 is formed. Thereafter, in this state, the workpiece 10 is restricted by the forging die 20 so that the workpiece 10 is not displaced in a direction perpendicular to the feeding direction. This helps to improve the accuracy of the forging shape that is subsequently performed by the inner punch 30.

Next, the operator manually adjusts the position of the lower end of the inner punch 30 by using the initial position adjusting portion 560 so that the lower end abuts against the surface of the workpiece 10. As shown in Fig. 5, in the present embodiment, the scale line indicating the initial position of the lower end of the inner punch 30 is at about 41.0 mm. Further, the set pressure of the sequence valve 530 (the set pressure in the pressure setting unit) is set to an initial value of about 4.5 MPa, and then gradually rises until it reaches about 11 MPa.

In the initial state, the position of the switching valve 510 is maintained at the cylinder down position 510b by the urging force of the spring 513. When the hydraulic pump 503 is driven in this state, since the hydraulic oil is supplied to the cylinder head chamber 501a of the cylinder body 501, the piston 507, the push rod 508, and the inner punch 30 connected to the lower end 508a thereof are integrally lowered. The top end (forged portion 32) of the inner punch 30 impacts the workpiece 10. At this time, the residual material 12 is generated on the workpiece 10. Thereafter, since the inner punch 30 receives resistance from the residual material 12, the pressure of the first oil passage 521 rises, and when the pressure of the first oil passage 521 reaches the initial set pressure as the sequence valve 530, that is, about 4.5 MPa, the sequence valve 530 is opened, and the control pressure acts on the first control chamber 511. The control pressure switches the spool of the switching valve 510 to the cylinder up position 510a while biasing the spring 513. Then, the hydraulic oil discharged from the hydraulic pump 503 is supplied to the pusher chamber 501b. Therefore, the displacement directions of the piston 507 and the inner punch 30 of the hydraulic cylinder 500 are reversed and rise away from the workpiece 10. As a result, the resistance disappears and the pressure in the head chamber 501a decreases. When the pressure of the first oil passage 521 is lower than the initial set pressure of the sequence valve 530, that is, about 4.5 MPa, the sequence valve 530 is closed, and the second valve is cut off. A control line 531. At this time, the spool of the switching valve 510 is switched to the cylinder down position 510b by the urging force of the spring 513 and the control pressure acting on the second control chamber 512. Then, since the hydraulic oil discharged from the hydraulic pump 503 is supplied to the cylinder head chamber 501a, the piston 507 of the hydraulic cylinder 500 and the inner punch 30 are again integrally displaced in the feeding direction (lower), and the inner punch 30 impacts the workpiece 10. According to the above method, the inner punch 30 repeatedly processes the workpiece 10 and then moves away from the workpiece 10, and processes the inner diameter of the workpiece 10. Further, as shown in Fig. 5, in the present embodiment, the inner punch 30 is repeatedly performed ten times in the period A from the start to the end of the processing performed on the workpiece 10 by the inner punch 30. The impact of the workpiece 10.

Generally, as the displacement amount of the inner punch 30 displaced in the feeding direction increases, that is, as the height position of the lower end of the inner punch 30 becomes lower, the amount of the residual material 12 generated by the workpiece 10 increases, and therefore, The resistance of the inner punch 30 from the workpiece 10 is gradually increased. Therefore, for example, when the set pressure of the sequence valve 530 is fixed, the displacement amount of the inner punch 30 displaced in the feed direction (the machining speed at which the inner peripheral surface 10a is machined by the inner punch 30) is gradually lowered. Therefore, as shown in FIG. 5, in the present embodiment, the set pressure of the sequence valve 530 is set by the pressure setting unit 536 as follows (as the inner punch 30 approaches the feed direction). The displacement amount of the displacement is increased. The set pressure of the sequence valve 530 (the press-in force of the inner punch 30 pressed into the workpiece 10) is gradually increased from about 4.5 MPa to about 11 MPa. Further, the inner circumferential surface 10a is smoothly processed. This increases productivity. In addition, as can be seen from FIG. 5, the position where the position of the inner punch reaches the minimum value coincides with the position at which the inner punch receives the maximum value from the resistance of the workpiece, and the position of the inner punch reaches the maximum value and the inner punch The head is in the same position from the resistance of the workpiece to a minimum value. Further, the shape of the line segment connecting the maximum value of the resistance received by the inner punch from the workpiece is substantially the same as the shape of the line segment connecting the maximum value of the set pressure in the pressure setting portion.

In the above-described step of processing the inner diameter of the workpiece 10 by the inner punch 30, first, the forged portion 32 that changes in the vertical direction repeatedly impacts the workpiece 10, thereby forming a reference inner circumferential surface on the workpiece 10. After the groove forming portion 34 that has been moved in the vertical direction repeatedly hits the workpiece 10, the groove 10c is formed on the reference inner circumferential surface 10b. The reference inner circumferential surface 10b is an inner circumferential surface having a uniform cross section in the axial direction perpendicular to the axial direction of the central axis O, and therefore is formed in the reference inner circumference by the groove forming portion 34. At the stage where the groove 10c is formed in the surface 10b, the reduction rate of the section of the workpiece 10 is fixed, that is, the pressure acting on the projection 34b is uniform. Therefore, the friction generated between the inner punch 30 and the workpiece 10 will be reduced as compared with the case where the groove is formed directly on the inner circumferential surface 10a of the workpiece 10 without forming the reference inner circumferential surface 10b.

Further, the above-described operation is performed to greatly reduce the friction generated between the inner punch 30 and the workpiece 10, and the inner punch 30 is repeatedly displaced and displaced from the workpiece 10, that is, within the inner portion. The punch 30 presses the residual material 12 of the workpiece 10 which is produced by the workpiece in the feed direction, so that the internal punch is excessively large, and the inner punch is separated from the workpiece. In order to reduce the resistance, the workpiece 10 is intermittently pressed in the feeding direction.

Therefore, since the wear of both the forged portion 32 and the groove forming portion 34 is suppressed, the inner circumferential surface 10a of the workpiece 10 and the reference inner circumferential surface 10b can be forged by a single step using a single inner punch 30. A groove 10c is formed. Therefore, the conventional broaching step is omitted, and the man-hours from the workpiece 10 to the desired molded article are reduced. Therefore, the conventionally performed step of arranging the forged intermediate molded article on the broaching apparatus independently of the forging device is omitted, thereby avoiding the groove caused by the tolerance of the intermediate molded article. The machining accuracy is lowered, and a high-precision groove can be formed.

Further, the forged portion 32 of the present embodiment has a guide portion 32c extending in the feeding direction from the distal end of the groove forming portion 34 in the feeding direction and having an outer peripheral surface parallel to the feeding direction. Therefore, in the step of machining the workpiece 10 by the inner punch 30, in a state where the guide portion 32c is guided by the reference inner circumferential surface 10b, that is, the guide portion 32c is prevented from being displaced in a direction perpendicular to the feeding direction. In the state of the groove, the groove is formed on the reference inner circumferential surface 10b by the groove forming portion 34 that is displaced along the feeding direction and the separating direction. Therefore, the processing accuracy of the groove 10c is further improved.

Further, in the present embodiment, in a state where the outer punch 40 presses the workpiece 10 toward the outer shape forming portion 22, that is, the workpiece 10 is restricted by the forging die 20 so that the workpiece 10 does not come into contact with the workpiece 10. When the feed direction is displaced in the vertical direction, the workpiece 10 is processed by the inner punch 30, so that the machining accuracy of the inner diameter of the workpiece 10 is further improved. Further, in the present forging device, both the inner diameter and the outer diameter of the workpiece 10 are processed without taking out the workpiece 10 from the die 20.

Further, since the inner punch driving unit 50 of the present embodiment has the speed adjusting unit, the material and shape of the workpiece 10 can be flexibly handled to process the workpiece 10.

In addition, it should be understood that the embodiments disclosed herein are presented by way of example only, and not in limitation. The scope of the present invention is defined by the scope of the claims and the scope of the claims and the scope of the invention.

For example, in the above-described embodiment, the guide portion 32c is an example having a shape having an outer peripheral surface parallel to the axial direction. However, the guide portion 32c may be gradually and slightly narrowed from the rear end of the guide portion 32c toward the tip end. The shape of the diameter.

Further, the shape and number of the protruding portions 34b of the groove forming portion 34 are not limited to the examples disclosed in the above embodiments. For example, when the key groove is formed, the protruding portion 34b is set to one.

Further, in the present embodiment, the guide portion 32c and the base portion 34a are formed in a columnar shape, that is, a cross section in a direction perpendicular to the axial direction of the guide portion 32c and the base portion 34a is circular. However, these cross-sectional shapes are not limited. In a circle. For example, the cross section of the guiding portion 32c and the base portion 34a may be elliptical or polygonal.

10‧‧‧Processed parts
10a‧‧‧ inner circumference
10b‧‧‧ benchmark inner circumference
10c‧‧‧ slot
20‧‧‧Forging die
22‧‧‧Shaping forming department
30‧‧‧Inner punch
32‧‧‧Forging Department
32a‧‧‧flat
32b‧‧‧ inclined section
32c‧‧‧Guidance Department
34‧‧‧Slot formation
34a‧‧‧ base
34b‧‧‧Protruding
40‧‧‧External punch
42‧‧‧Pushing Department
44‧‧‧Lubricating oil supply flow path
50‧‧‧Inner Punch Drive Department
500‧‧‧Hydraulic cylinder
501‧‧‧ cylinder body
501a‧‧‧Cylinder room
501b‧‧‧Pushing room
502‧‧‧Hydraulic system
503‧‧‧Hydraulic pump
504‧‧‧Motor
505‧‧‧Spoke flow adjustment unit
507‧‧‧Piston
508‧‧‧Put
508a‧‧‧Bottom
510‧‧‧Switching valve
510a‧‧‧Cylinder up position
510b‧‧‧Cylinder down position
511‧‧‧First Control Room
512‧‧‧Second Control Room
513 ‧ ‧ spring
521‧‧‧First oil road
522‧‧‧Second oil road
523‧‧‧ Third oil road
524‧‧‧ fourth oil road
530‧‧‧Sequence valve
531‧‧‧First control line
532‧‧‧Second control line
535‧‧‧ throttle valve
536‧‧‧ Pressure setting unit (pressing force setting unit)
540‧‧‧Flow regulating valve
546‧‧‧Flow adjustment unit (speed adjustment unit)
550‧‧‧ buffer
551‧‧‧Accumulator
552‧‧‧throttle valve
553‧‧‧ check valve
560‧‧‧Initial Position Adjustment Department
561‧‧‧Electromagnetic switching valve
561a‧‧‧Neutral position
561b‧‧‧Cylinder down position
561c‧‧‧Cylinder up position
564‧‧‧Control pipeline
566‧‧‧Back pressure holding department
567‧‧‧Adjustment Department
571, 572‧‧ ‧ detection valve
573‧‧‧Switching valve
575‧‧‧ oil passage
567‧‧‧Safety valve
577‧‧‧Reducing valve
578‧‧‧ throttle valve
579‧‧‧ solenoid valve
O‧‧‧ center axis
T‧‧‧ oil tank

Fig. 1 is a view showing the outline of a forging device according to an embodiment of the present invention. Fig. 2 is a view showing the outline of the forging device of Fig. 1; Figure 3 is a bottom plan view showing the inner punch of the forging device of Figure 1; 4 is a view showing the configuration of an inner punch drive unit. Fig. 5 is a graph showing the relationship between the inner punch and the resistance acting on the inner punch.

10‧‧‧Processed parts

10a‧‧‧ inner circumference

10b‧‧‧ benchmark inner circumference

10c‧‧‧ slot

12‧‧‧ residual materials

14‧‧‧Crushing waste

20‧‧‧Forging die

22‧‧‧Shaping forming department

24‧‧‧ inner circumference

30‧‧‧Inner punch

32c‧‧‧Guidance Department

34‧‧‧Slot formation

34a‧‧‧ base

34b‧‧‧Protruding

40‧‧‧External punch

44‧‧‧Lubricating oil supply flow path

O‧‧‧ center axis

Claims (5)

A forging device characterized by comprising: a forging die for placing a workpiece having a through hole; an inner punch for processing an inner circumferential surface of the through hole surrounding the workpiece; and an inner punch a head driving portion for repeatedly displacing the inner punch between the impact position and the exit position, wherein the impact position is a position at which the inner punch is displaced toward the feeding direction of the workpiece to impact the workpiece The leaving position is a position in which the inner punch is displaced toward the leaving direction opposite to the feeding direction and further away from the workpiece; wherein the inner punch has a forged portion for forging the inner circumference of the workpiece And a groove forming portion formed at a rear of the forged portion in the feeding direction; the forged portion is formed at a position facing the workpiece to be placed on the forging die in the feeding direction, and has a shape in which the inner peripheral surface of the cross section perpendicular to the feeding direction forms a uniform reference inner peripheral surface in the entire feeding direction by forging the inner peripheral surface of the workpiece; and the groove forming portion has as follows Like: in the feeding direction of the forged portion protruding from the rear end to the outside may be formed on the inner peripheral surface of the groove reference. The forging device according to claim 1, wherein the forging portion includes a guiding portion that extends from the top end of the groove forming portion in the feeding direction in the feeding direction, and has The outer peripheral surface of the feed direction is parallel. The forging device according to claim 1 or 2, further comprising: an outer punch disposed outside the inner punch; the forging die having an outer shape forming portion surrounding the outer periphery of the workpiece The surface may have a shape that shapes the shape of the workpiece; the outer punch has a shape in which the workpiece is pressed toward the feed direction to expand the workpiece and cause the workpiece to be expanded The outer surface of the workpiece is in close contact with the outer shape forming portion. The forging device according to claim 1 or 2, wherein the inner punch driving portion has a press-in force setting portion, and the press-in force for pressing the inner punch into the workpiece is performed with the inner punch The head increases from an initial position in contact with the workpiece to the displacement of the displacement of the inner punch in the feed direction. A forging device according to claim 1 or 2, wherein the inner punch driving portion has a speed adjusting portion that adjusts a speed at which the inner punch is displaced from the impact position to the separated position.